Aviation specialists are picking apart pixel-by-pixel the dozen-or-so photos of the copter that have appeared online. They’re assembling digital mock-ups of the aircraft and comparing them to lost stealth designs of the 1980s and ’90s. Speculation abounds, and so far no one from the government is commenting. But depending on what the copter turns out to be, it could shed new light on everything from the abilities of U.S. commandos to the relationship between the United States and Pakistan.

Opinions about the copter seem to fall into three basic camps. The most-cautious observers believe the wreckage is from a conventional chopper that got so badly mangled during the crash that it became unrecognizable. In the center, there are those who think the helicopter is an Army MH-60 Blackhawk tweaked to make it quieter and more stealthy. On the fringes, the true believers are talking about a brand-new, radar-evading helicopter design.

That leaves an upgraded, stealth-optimized MH-60 as the most likely candidate — a conclusion that jibes with CIA director Leon Panetta’s assertion Tuesday that the 25-man strike team was “carried in two Blackhawk helicopters that went in.”

A story by ace reporter Sean Naylor in Army Times, published just minutes after the initial version of this post, supports this conclusion. Naylor quotes a retired Special Forces aviator saying the special Blackhawk, modified by Lockheed Martin, has “hard edges, sort of like an … F-117″ stealth fighter from the same company.

According to a source who spoke to our own Spencer Ackerman, the modifications might have taken place with the help of a mysterious Army organization called the “Technology Applications Program Office,” located at Fort Eustis, Virginia. The rumored nickname? Airwolf. That’s right, like the cheesy ‘80 TV show.

Blackhawk Down?

Aside from one IT consultant who unwittingly live-tweeted the bin Laden raid, reports from Pakistani sources of a crashed helicopter were the first evidence that something was going down in Abbottabad. “According to eyewitnesses, a low-flying helicopter crashed in a populated area, and as a result two houses were engulfed in flames,” a Pakistani news service reported.

One local news agency claimed the downed bird was Pakistani. It wasn’t until several hours later that U.S. government sources clarified the initial stories. “We lost one helicopter due to mechanical failure,” a senior U.S. official said. “The aircraft was destroyed by the crew, and the assault force and crew members boarded the remaining aircraft to exit the compound.”

The official’s insistence — echoed later by Panetta — that there were just two choppers involved in the 25-man raid raised some eyebrows.

According to Capt. Crispin Burke, a U.S. Army Blackhawk pilot and Danger Room pal, two of the copters together can just barely squeeze in 25 people plus their weapons and other gear. But it’s inconceivable that a single surviving Blackhawk could have transported all 25 members of the assault team. Anyone who’s ridden in a Blackhawk knows that.

More than two choppers were present over bin Laden’s compound, despite what the administration was saying. That was the first indication that, as far as helicopters were concerned, something unusual was afoot.

Then came the photos. When the sun rose in Abbottabad, enterprising photographers with the European Press Agency and the Associated Press snapped pics showing the remains of the destroyed U.S. helicopter. The snapshots apparently depicted features not found on standard Blackhawks. Late on May 3, the first headlines appeared announcing the existence of a previously unknown “stealth helicopter.”

The Invisible Rotorcraft

So what was it that betrayed the downed choppers’ secret roots? Nearly rivetless skin, odd control surfaces, a shrouded tail rotor and special infrared-absorbing paint, for starters.

“Note how the UH-60 has a large stabilator [horizontal fin] with plenty of rivets,” Burke commented. “The one in the crash is much smaller, very smooth and swept back. Strange.”

A “round shield-like affair over the tail-rotor hub is an airflow diverter, designed to eliminate the turbulence around the rotor hub, making it more efficient,” wrote “Bill” from the milblog Arrgggh!. The diverter “probably has a secondary effect of reducing the noise of the tail rotor by making it directional.”

A very clear photo of that “shield” was given to Reuters, and appear at the top of this story.)

“The aircraft skin is interesting,” Bill continued. “It’s perfectly smooth, and I have a nagging hunch it’s something I’ve seen before, back in the late ’80s” — on an experimental OH-6 “Loach” scout chopper.

To him, the paint on the wrecked chopper appeared to be a “variation on the Invisible Loach — a light-emitting appliqué film which, coupled to directional cameras, will exactly reproduce the light and color patterns on the opposite side of the aircraft. Think of the aircraft as being made of glass.”

The stealthy copter also has a “special coating” on its windshield to scatter radar waves, Naylor asserts in his Army Times story.

Combined, the details imply a helicopter design that is more stealthy than standard choppers in every sense of the term. “Such a helicopter would not be invisible or silent, but would be harder to detect and track using an X-band or Ku-band radar, and quieter than a conventional helicopter,” said Carlo Kopp, joint head of theAir Power Australia think tank.

Based on the evidence, and the assumption that these improvements were applied to a basic Blackhawk airframe, aviation artist Ugo Crisponi produced a quickrendering of what the secret chopper might look like. The components depicted in the new Guardian photos — plus Naylor’s detailed description — match Crisponi’s concept pretty closely.

Historians and analysts were quick to point out precedents for the elusive bird. The obvious example is the Army’s überexpensive RAH-66 Comanche, killed off in 2004. That bird, Copp said, featured “shrouded rotor heads and unspecified absorbent materials” just like the mystery craft from Abbottabad.

John Pike, from Virginia-based Globalsecurity.org, highlighted the “MH-X,” a low-signature transport chopper project from the 1980s that was reportedly tested alongside the F-117 stealth fighter and B-2 stealth bomber.

Based on Naylor’s reporting, it appears that a handful of special Blackhawks — probably no more than four — indeed originated from the MH-X program, but plans for a large, permanent unit to fly these birds was cancelled “within the last two years.” Instead, Army Special Forces aviators took turns training on the stealth copters in Nevada, possibly at the secretive base known by some as “Area 51.”

Stealth Copter, Clear Politics

Though the evidence is mounting that the newly revealed black chopper is more angular Blackhawk derived from the MH-X program, it could be a while before we know for sure. The Pentagon is slow to reveal its most-advanced aircraft.

Nearly two years have passed since the Air Force admitted it possessed a stealthy spy drone, the RQ-170 — and we still don’t have an official photo of that bird. Moreover, statements from Washington seem intended to obscure the issue of the mystery chopper.

In any event, the implications are potentially enormous. For one, the existence of a stealthy helicopter means we must revise upward our assessment of U.S. Special Operations Forces’ ability to strike fast and unseen, all over the world.

Second, we should take with a grain of salt all the recent hand-wringing over the supposed decay in the American military rotorcraft industry. If we really have already fielded the world’s first radar-evading helicopter, there’s less reason to worry that the United States might have lost its chopper-making skills.

Third, the fact that the Pentagon was willing to risk its most secret whirlybird “shows the importance of the mission in the eyes of U.S. commanders,” according toAviation Week’s Bill Sweetman, who was, as usual, among the first to report on the new chopper.

Finally, the black helicopter sheds new light on the military’s suspicion of possible Pakistani interference in the bin Laden raid. In his speech announcing bin Laden’s death, President Barack Obama heaped praise on Pakistan. “Our counter-terrorism cooperation with Pakistan helped lead us to bin Laden.”

Moreover, Joint Special Operations Command wasn’t comfortable simply arriving on the scene in its decidedly radar-visible Army Chinooks or Air Force MV-22 tilt-rotors. That would’ve meant essentially barging into Pakistani airspace, and hoping that Islamabad would refrain from targeting the attackers with surface-to-air-missiles.

No, JSOC felt it was necessary to stay off Pakistani radar displays for as long as possible. The unavoidable inference is that the commandos feared Pakistan might actually shoot at unannounced American choppers. That revelation, more so than the mere existence of a stealthy helicopter, could be the most compelling news of all.